Syntheses of 4 and 5-alkylsulfonylimidazoles

A series of isomeric 4 and 5-alkylsulfonyl, alkylsulfinylimidazoles 9,10 were prepared by two general methods. Chlorosulfonation of imidazole afforded 4(5)-chlorosulfonylimidazoles 2, 4, 5 . The chlorosulfonyl derivatives were reduced, alkylated and oxidized to give 9 and 10 . In the second method 2, 4, 5 were converted to sodium sulfinate 8 and reacted with alkyl halides to afford the title compound 9 .     

Synthesis of AS1411-Aptamer-Conjugated CdTe Quantum Dots with High Fluorescence Strength for Probe Labeling Tumor Cells

In this paper, we report microwave-assisted, one-stage synthesis of high-quality functionalized water-soluble cadmium telluride (CdTe) quantum dots (QDs). By selecting sodium tellurite as the Te source, cadmium chloride as the Cd source, mercaptosuccinic acid (MSA) as the capping agent, and a borate-acetic acid buffer solution with a pH range of 5–8, CdTe nanocrystals with four colors (blue to orange) were conveniently prepared at 100 °C under microwave irradiation in less than one hour (reaction time: 10–60 min). The influence of parameters such as the pH, Cd:Te molar ratio, and reaction time on the emission range and quantum yield percentage (QY%) was investigated. The structures and compositions of the prepared CdTe QDs were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and X-ray powder diffraction experiments. The formation mechanism of the QDs is discussed in this paper. Furthermore, AS1141-aptamer-conjugated CdTe QDs in the U87MG glioblastoma cell line were assessed with a fluorescence microscope. The obtained results showed that the best conditions for obtaining a high QY of approximately 87 % are a pH of 6, a Cd:Te molar ratio of 5:1, and a 30-min reaction time at 100 °C under microwave irradiation. The results showed that AS1141-aptamer-conjugated CdTe QDs could enter tumor cells efficiently. It could be concluded that a facile high-fluorescence-strength QD conjugated with a DNA aptamer, AS1411, which can recognize the extracellular matrix protein nucleolin, can specifically target U87MG human glioblastoma cells. The qualified AS1411-aptamer-conjugated QDs prepared in this study showed excellent capabilities as nanoprobes for cancer targeting and molecular imaging.     

In silico studies of novel scaffold of thiazolidin-4-one derivatives as anti-Toxoplasma gondii agents by 2D/3D-QSAR,molecular docking,and molecular dynamics simulations

Structural Chemistry - Toxoplasma gondii is an obligate intracellular protozoa that can infect a wide variety of warm-blooded animals and humans. It was claimed that novel anti-Toxoplasma gondii...     

Rapid diagnosis of mycobacterium tuberculosis with electrical impedance spectroscopy in suspensions using interdigitated microelectrode

A Mycobacterium tuberculosis (MTB) bacilli are still widely spreading and have to be diagnosed fast and efficiently. Therefore, a new simple and rapid method was proposed to detect MTB by the impedance properties of MTB suspensions using interdigitated microelectrodes. As a result, MTB suspensions in deionized (DI) water with different cell concentrations generated different electrical impedance spectral responses. Whereas MTB suspensions in 0.9 wt. % NaCl solution did not produce any significant differences in the impedance spectra in response to different cell concentrations. In DI water suspensions, the impedance at 1 kHz decreased with increasing cell concentrations. The impedance of MTB suspension in DI water has been discussed; it was found to be resulted from the cell wall charges and release of ions from the cells. There was a linear relationship between the impedance and logarithmic value of the cell concentration in the cell concentration range of 10² to 10⁸ cfu/mL, which can be expressed by the regression equation of Z (kΩ) =–456lnN (cfu/mL) + 9717 with R² = 0.99. Detection limit was calculated as 10⁴ cfu/mL, which is comparable with many label-free immunosensors for detecting pathogenic bacteria reported in the literature. This work demonstrated that MTB concentration can be determined through measuring the impedance of MTB suspensions in DI water. This new detection mechanism can be an alternative for current impedance methods available for detecting bacterial cells.     

A meshless like method for the approximate solution of integral equations over polygons

In this paper, a numerical scheme based on a Gauss-like cubature formula from Sammariva and Vianello (2007) [1] is introduced for approximate solution of integral equations over a polygonal domain with a piecewise straight lines boundary in R²${\mathbb{R}}^2$. The proposed technique is a meshless like method with sufficient precision, which does not require any discretization of the polygon domain or any preprocessing such as mesh refinement. The error analysis of the method is provided and some numerical experiments are also presented to evaluate the performance of the proposed algorithm.     

Synthesis of α‐[5‐(5‐amino‐1,3,4‐thiadiazol‐2‐yl)‐2‐imidazolylthio]acetic acids

The paper describes synthesis and antituberculosis activity of α‐[5‐(5‐amino‐1,3,4‐thiadiazol‐2‐yl)‐imidazol‐2‐ylthio]acetic acids ( 5a,b ). The compounds were tested against Mycobacterium tuberculosis strain H37Rv in comparison to rifampicin. Compounds exhibited low activity (MIC ≤ 6.25 μg/ml, % inhibition ≥ 24).     

Syntheses of substituted pyrrolo[2,3‐d]imidazole‐5‐carboxylates and substitued pyrrolo[3,2‐d]imidazole‐5‐carboxylates

Starting from readily available p‐substituted‐benzylamines a series of ethyl 2‐alkylthio‐1‐substituted‐ben‐zylpyrrolo[2,3‐d]imidazole‐5‐carboxylates was prepared. In addition, starting from 2‐alkyl‐4(or 5)‐formylimidazoles and methyl 4′‐bromomethylbiphenyl‐2‐carboxylate a series of methyl substituted‐pyrrolo[2,3‐d]imidazole‐5‐carboxylates and methyl substituted‐pyrrolo[3,2‐d]imidazole‐5‐carboxylates was prepared.     

Exploring the scope of the Gewald reaction: Expansion to a four-component process

An efficient four-component reaction was developed to take advantage of the reactivity of the 2-aminothiophene-3-carbonitrile functionality, which is obtained during the classical three-component Gewald reaction. Various α-methylene bearing ketones were reacted with malononitrile, elemental sulfur, and aryl/heteroarylnitrile derivatives in t-BuOH/NaOH to afford 2-arylthieno[2,3-d]pyrimidin-4-amines in high yields. Preliminary studies revealed the photophysical properties of the products and their potential for use as metal sensors.     

Momentum space calculations of the binding energies of argon dimer

The binding energies of argon dimer are calculated by solving the homogeneous Lippmann-Schwinger integral equation in momentum space. Our numerical analysis using two models of argon-argon interaction developed by Patkowski et al. not only confirms the eight argon dimer vibrational levels of the ground state of argon dimer (ie, for j = 0) predicted by other groups but also provides a very precise means for determining the binding energy of the ninth state which its value is a matter of discussion. Our calculations have been also extended to states with higher rotational quantum number j and we have calculated the energy of all 174 bound states for both potential models. Our numerical results for vibrational levels of the ground state of argon dimer are in excellent agreement with other theoretical calculations and available experimental data.